A CESSNA 401 PLT HAD TO SHUT DOWN AN ENG WHEN ITS EXHAUST MANIFOLD BROKE. SUBSEQUENT DAMAGE BURNED WIRING AND BROKE A FUEL LINE.

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I WAS ENRTE ON A VFR FLT TO REPOSITION THE ACFT FOR A PART 135 FLT. I WAS THE ONLY SOUL ON BOARD. AFTER 15-20 MINS OF FLT; I NOTICED I WAS LOSING MANIFOLD PRESSURE. THE L ENG SEEMED TO BE RUNNING SMOOTHLY; BUT I LOST 5-6 INCHES OF MANIFOLD PRESSURE. CHANGING THE THROTTLE DIDN'T CHANGE ANYTHING. AFTER SEVERAL MINS; I NOTICED A BROWNISH FLUID LEAKING OUT OF THE L WING; OUTSIDE OF THE ENG. I DECIDED THAT THERE WAS A PROB WITH THE TURBO AND IT WAS HEATING THE WING. I LOST THE L MAIN AND L AUX FUEL GAUGES -- THEY WENT TO '0.' THEN THE STALL WARNING CAME ON. I SHUT THE L ENG DOWN AND FEATHERED THE PROP. I DIDN'T SEE ANY EVIDENCE OF A FIRE; SO I PROCEEDED TO THE NEXT CLOSEST ARPT AND LANDED. WHEN I WAS TAXIING IN; I NOTICED A STRONG SMELL OF FUEL. WHEN I SHUT THE ENG DOWN; THE L ENG WAS LEAKING FUEL. AFTER I FOUND SOME MECHS; WE DRAINED THE L MAIN AND L AUX FUEL TANKS. WHEN THE ENG WAS OPENED; WE FOUND THAT THE EXHAUST MANIFOLD DEVELOPED A HOLE; THEN BROKE CLEAN THROUGH. THIS CAUSED THE FUEL LINES TO RUPTURE AND BURNED SOME WIRING. I WAS FORTUNATE THAT I SHUT THE ENG DOWN WHEN I DID BECAUSE THE FUEL NEVER IGNITED. AN FAA INSPECTOR AND A REPRESENTATIVE FROM THE NTSB WERE SURPRISED THAT IT DIDN'T IGNITE. INITIALLY THE ONLY INDICATION I HAD WAS THE LOSS IN MANIFOLD PRESSURE. ONCE THE FLUID STARTED LEAKING OUT OF THE WING; I DECIDED TO SHUT IT DOWN. IF THE FUEL HAD IGNITED; I WOULDN'T BE HERE TODAY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR WAS FLYING A CESSNA 401 ON A PART 135 POSITIONING FLT. AN FAA AND AN NTSB REPRESENTATIVE CAME BY TO SEE THE ACFT. THEY RPTED TO THE RPTR THAT THERE HAVE BEEN 5 OTHER SIMILAR OCCURRENCES OF THIS PROB; SOME WHERE THE ACFT BROKE UP INFLT. NO ACTION HAS BEEN TAKEN AGAINST THE RPTR.